The Connectedness with Nature of Chinese Adolescent Tourists: A Q Method Approach

A systematic understanding of Chinese adolescent tourists’ connectedness with nature is helpful to illustrate the coming cultural turn in self-nature relationship. However, the existing research is almost based on the Western cultural context and follow the Western approach. Employing the Q method, this study aims to investigate the diverse patterns of CWN from the perspective of 36 adolescent tourists in Xi’an and Shenzhen, China. Our initial findings show four distinct patterns are relevant in the participants’ CWN, including individuals’ ecological self, subjective feelings about nature, positive experiences with nature, and cognitive beliefs about nature. In addition, a theoretical framework of four underlying continuums is developed to clarify how a complex process of co-construction reveals patterns of CWN. This study offers suggestions for destination management and environmental education

Real-time coordinated voltage control of PV inverters and energy storage for weak networks with high PV penetration

There are more large-scale PV plants being established in rural areas due to availability of low priced land. However, distribution grids in such areas traditionally have feeders with low X/R ratios, which makes the independent reactive power compensation method less effective on voltage regulation. Consequently, upstream Step Voltage Regulator (SVR) may suffer from excessive tap operations with PV induced fast voltage fluctuations. Although a battery energy storage system (BESS) can successfully smooth PV generation, frequent charge/discharge will substantially affect its cost effectiveness. In this paper, a real-time method is designed to coordinate PV inverters and BESS for voltage regulation. To keep up with fast fluctuations of PV power, this method will be executed in each 5s control cycle. In addition, charging/discharging power of BESS is adaptively retuned by an active adjustment method in order to avoid BESS premature energy exhaustion in a long run. Finally, through a voltage margin control scheme, the upstream SVR and downstream PV inverters and BESS are coordinated for voltage regulation without any communication. This research is validated via an RTDS-MatLab co-simulation platform, and it will provide valuable insights and applicable strategies to both utilities and PV owners for large-scale PV farm integration into rural networks

Synthesis of Alkyl Substituted Dicyclohexano-18-crown-6 Homologues for Strontium Extraction in HNO3 Media

AbstractA series of dicyclohexano-18-crown-6 (DCH18C6) homologues containing different alkyl substituents were synthesized for a comparative study of the extraction ability towards strontium. The synthesis and the structure characterization of the intermediates and the products were detailed. The crown ether homologues were labeled as CX-DCH18C6 (X=3∼7), where the X represents the number of the carbon atoms in the alkyl substituents. The extraction ability of the CX-DCH18C6 samples towards strontium in solvent extraction system was investigated. The substituent effect of the samples was discussed, and the factors affecting the separation such as solvent, acidity and initial metal concentration were examined

Finite Element Analysis of the Mouse Distal Femur with Tumor Burden in Response to Knee Loading

Breast cancer-associated bone metastasis induces bone loss, followed by an increased risk of bone fracture. To develop a strategy for preventing tumor growth and protecting bone, an understanding of the mechanical properties of bone under tumor burden is indispensable. Using a mouse model of mammary tumor, we conducted finite element analysis (FEA) of two bone samples from the distal femur. One sample was from a placebo-treated mouse, and the other was from a mouse treated with the investigational drug candidate, PD407824, an inhibitor of checkpoint kinases. Mechanical testing and microCT images revealed that bone strength is improved by administration of PD407824. In response to loading to the knee, FEA predicted that the peaks of von Mises stress, an indicator of fracture yielding, as well as the third principal compressive stress, were higher in the placebo-treated femur than the drug-treated femur. Higher peak stresses in trabecular segments were observed in the lateral condyle, a critical region for integrity of the knee joint. Collectively, this FE study supports the notion that mechanical weakening of the femur was observed in the tumor-invaded trabecular bone, and chemical agents such as PD407824 may potentially assist in preventing bone loss and bone fracture

Investigation on impacts of alternative generation siting in power grids from the view of complex network theory

In this article, the impacts of alternative generation integration in a power grid are discussed from the view of complex network theory. Using the improved complex network index, the structural performance of the system could be assessed in planning. Also, the distribution of load and generation are also considered in the modeling. Compared with the existing planning method, the proposed method can not only solve alternative generation units siting issues but also locate the corresponding conventional generation to be curtailed or replaced. Furthermore, as more information is obtained, e.g., related policy or cost parameters, a multi-objective comprehensive decision model is designed, the weight coefficient of which is determined by the two-tuple linguistic decision method. The proposed indices and models can effectively realize fast location and help improve the structural performance of the system with appropriate alternative generation integration. The models and methods are tested and verified by test cases

Power system disturbance localization using recurrence quantification analysis and minimum-volume-enclosing ellipsoid

A method for determining a location of a disturbance in a power system is provided. The method includes receiving data from a plurality of sensors distributed across the power system; performing a recurrence quantification analysis on the received data to identify a predetermined number of sensors, from the plurality of sensors, that are closest to the disturbance; constructing a plurality of minimum-volume-enclosing ellipsoids based on and enclosing the data received from the identified sensors; extracting one or more parameters from the plurality of minimum-volume-enclosing ellipsoids; inputting the one or more parameters into a multivariate-random-forest regression algorithm to determine the location of the disturbance and a power mismatch corresponding to the disturbance; and presenting, on one or more display units, the determined location of the disturbance and the determined power mismatch

Learning from a 3.275 MW utility-scale PV plant project: Update and new remarks

This paper presents thorough investigations of a utility-scale PV and battery system operation, connected to an 11 kV distribution feeder. The plant contains 3.275 MWp solar PV system and 600kW/760kWh battery storage, which is located at the University of Queensland Gatton campus and funded by the Australian Federal Government Department of Education, Education Infrastructure Fund. The PV plant consists of three different PV tracking technologies (namely fixed-tilt, single-axis tracking, and double-axis tracking) and state-of-the-art Li-Polymer battery system. An initial report on the performance and grid integration challenges of the plant of this size was presented in CIGRE 2016 Paris Session [1]. Now, more than two years of PV generation data along with one and a half years of battery operational data is available for analysis. This way, meaningful annual and seasonal operation and performance of the plant can be assessed. This paper is organised in four sections. Section 1 outlines the context of the paper from a general perspective. It is, then, followed by explaining the configuration of the PV and battery systems within the plant in section 2, where the focus is on the battery system configuration and operation algorithm. Section 3 offers in-depth analyses of the plant operation in terms of PV annual and seasonal production, battery operational performance, and voltage regulator operation from different perspectives. In particular, annual performance and the plant yield is calculated based on different tracking systems in subsection 3.1, followed by seasonal effect investigation. Battery operation in terms of energy, power, State-of-Charge (SOC) level, and cell temperature is assessed in subsection 3.2 considering seasonal impact. In subsection 3.3, voltage at the Point of Common Coupling (PCC) is analysed. Most notably, the impact of PV variations on the operation of Step Voltage Regulator (SVR) is evaluated. Finally, the paper is concluded in section 4. Through these analyses, key observations are provided to better understand the plant performance and relevant network impacts

The importance of the positional probability of word final (but not word initial) characters for word segmentation and identification in children and adults' natural Chinese reading

Word spacing is important in guiding eye movements during spaced alphabetic reading. Chinese is unspaced and it remains unclear as to how Chinese readers segment and identify words in reading. We conducted two parallel experiments to investigate whether the positional probabilities of the initial and the final characters of a multi-character word affected word segmentation and identification in Chinese reading. Two-character words were selected as targets. In Experiment 1, the initial character's positional probability was manipulated as being either high or low, and the final character was kept identical across the two conditions. In Experiment 2, an analogous manipulation was made for the final character of the target word. We recorded adults' and children's eye movements when they read sentences containing these words. In Experiment 1 reading times on targets did not differ in the two conditions for both children and adults, providing no evidence that a word initial character's positional probability contributes to word segmentation. In Experiment 2, adults had shorter reading times, and made fewer refixations on targets that were comprised of final characters with high relative to low positional probabilities; a similar effect was observed in children, but this effect had a slower time course. The results demonstrate that the positional probability of the final (but not the initial) character of a word influences segmentation commitments in reading. It suggests that Chinese readers identify where a currently fixated word ends, and via this commitment, by default, they identify where the subsequent word begins

Finite Element Analysis of the Mouse Proximal Ulna in Response to Elbow Loading

Bone is a mechano-sensitive tissue that alters its structure and properties in response to mechanical loading. We have previously shown that application of lateral dynamic loads to a synovial joint, such as the knee and elbow, suppresses degradation of cartilage and prevents bone loss in arthritis and postmenopausal mouse models, respectively. While loading effects on pathophysiology have been reported, mechanical effects on the loaded joint are not fully understood. Because the direction of joint loading is non-axial, not commonly observed in daily activities, strain distributions in the laterally loaded joint are of great interest. Using elbow loading, we herein characterized mechanical responses in the loaded ulna focusing on the distribution of compressive strain. In response to 1-N peak-to-peak loads, which elevate bone mineral density and bone volume in the proximal ulna in vivo, we conducted finite-element analysis and evaluated strain magnitude in three loading conditions. The results revealed that strain of ~ 1000 μstrain (equivalent to 0.1% compression) or above was observed in the limited region near the loading site, indicating that the minimum effective strain for bone formation is smaller with elbow loading than axial loading. Calcein staining indicated that elbow loading increased bone formation in the regions predicted to undergo higher strain